A sign on the door of the pool today said it would be closed from May 26 to July 9.

This afternoon the Acting Director General of Health, Bryant Stokes, said the classes were not affected by the job freeze, and that the closure was due to a delay in finding a replacement who was adequately trained.

Opposition Leader Mark McGowan had called on the government to take action, blaming financial mismanagement for the decision to close the pool.

"Surely, as a state we can provide hydrotherapy for children with disabilities without it being cancelled because of budget mismanagement," he said.

"The reason this jobs freeze in place is because of the government has mismanaged the finances, and the people who suffer are people like Amy and Ruby, and that isn't fair and it isn't right.

"They put new chairs and tables into Parliament House that cost nearly $30,000, yet they can't provide a replacement to run the hydrotherapy pool at Princess Margaret."

A Health Department spokeswoman said there had been a mistake and a fill-in supervisor had now been found.

Professor Stokes said he expected the pool to reopen later in the week.

"As a frontline clinical position, the hydrotherapy supervisor position was not affected by the recruitment freeze," he said.

"Unfortunately there has been a gap in between the supervisor going on leave and an appropriately qualified staff member commencing in the position this week."

Mr McGowan said the government had been caught out, while Ms Edwards said she was "overjoyed" the classes would continue.